This Is Us Creator Dan Fogelman Teases What's to Come for Each Character in the Rest of Season 4

Five pounds of shrimp later, This Is Us delivered yet another Pearson family Thanksgiving with major plot twists.

The season 4 fall finale — titled “So Long Marianne” after Leonard Cohen’s 1967 song — uncovered a few of Jack Pearson’s special memories that were threaded from generation to generation as Uncle Nicky (Griffin Dunne) quickly learned: “Traditions inspired by Jack Pearson are sort of the backbone of this shindig.”

Happy memories were made under one roof with Deja (Lyric Ross) spending the holiday with her biological mother Shauna, Kevin (Justin Hartley) helping niece Tess (Eris Baker) come out to her school friends, and baby Jack celebrating his first Thanksgiving.

However, audiences learned alarming new life events in the final few minutes, including the foreshadowing of Rebecca’s memory loss, conflict between Kevin and Randall (Sterling K. Brown) and Kate (Chrissy Metz) discovering Toby’s female friend in his CrossFit text chain.

As fans are left with more loose ends and unanswered questions, showrunner and creator Dan Fogelman tells PEOPLE what’s to come with each character and previews the special individualized episodes in the back half of the season.

RELATED: Randall’s Concern for Mom Rebecca’s Memory Issues Backfires in This Is Us Season 4 Fall Finale

Rebecca Pearson (Mandy Moore)

As much as Randall is worried about his mom’s memory loss in the present day, Fogelman warns viewers to be concerned.

“I think you would be made of stone if you weren’t a little concerned after watching the episode. There’s a lot going on here, obviously, it’s concerning,” he says. “We’re at the early, early stages of something going on. Beyond all of the concern for the character herself, it would be correct to have concern for the entire family right now. We’ve been born with this family, in terms of how they started as children with what place Rebecca holds for them. They’ve lost a parent, Randall’s lost two [fathers] so you can imagine the ramifications for Rebecca as an individual, there are also obviously ramifications for the entire family.”

Fogelman explains Rebecca’s shift in her mental wellbeing has “always been part of the series’ plan,” calling This Is Us as a show that “plays in time and memory so this was always part of the plan of where we were going to go.”

Raving about Moore and her performance, Fogelman adds: “It’s always been part of our plan where this storyline will go but what can’t be part of your plan was how extraordinary Mandy was going to be in all of this. It’s not spoken about how extraordinary she is doing on this show right now, which is playing multiple versions and timelines of the same character so seamlessly that your heart is breaking for [Rebecca] on-screen. I’m very excited for people to see what comes next and what she’s doing as an actor.”

Jack Pearson (Milo Ventimiglia)

When discussing Rebecca overall, a major part of her story is her late husband and love of her life, Jack. “We’re going to continue to see their backstory but not because anything involving her memory. The direction we’re going in, we’re trying to go responsibly and we’ve been very careful to ensure that,” Fogelman says of her memories with Jack.

“One of the great challenges of this show has always been to be willing to explore the difficult and sad stuff that happens to a family when you’re exploring six decades of a family but not make it where we can’t also experience magnificent moments of joy and hope in those same episodes,” he shares. “That’s kind of what life is: It’s moments of great joy, great hope and great happiness punctuated by moments of occasional deep loss and deep sadness. We feel very confident we can do that.”

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Kevin Pearson

This Is Us doesn’t return until the new year and fans will be left wondering what led to the estranged relationship between Kevin and Randall. We learned that Kevin is newly engaged and has a baby on the way, he is also struggling to mend fences with his brother.

Asked if they’re not on speaking terms due to Randall keeping mom Rebecca’s memory loss a secret early on, Fogelman teases that the theory is “definitely a possibility of the right area.”

“The primal wounds with our immediate family and siblings just don’t go away through a pocket of time. Randall and Kevin have been bickering for the past year or two. These are two children who were the exact same age and grew up in the same house, they’re both alpha males competing for their mother and father’s attention,” he explains. “One of them was the do-gooder who could do no wrong and the other was kind of the charmer and someone to worry about a little bit. When suddenly something is going on with the lone remaining parent with whom they both have issues — and one of them has kept a secret and there are other things coming into play — it would probably be not inconceivable that it could a cause of they’re not speaking a year from now.”

RELATED: This Is Us‘ Justin Hartley Breaks Down Kevin’s ‘Impulsive, Sometimes Catastrophic Decisions’

In the romance department, audiences will be kept guessing who the identity of Kevin’s fiancée is (Cassidy? Zoey? Someone new?).

“Kevin is on this quest to find his partner and his biological clock is ticking as a 39-year-old movie star,” Fogelman laughs. “Who he winds up with, old flames and new flames, is a big part of our back half of this season and one of the big things we will solve by the end of the season.”

So will we see more of Jennifer Morrison’s Cassidy this season? “It’s quite possible,” he says. “What I can say is that already Cassidy has served an incredibly important role for him in terms of this rehabilitation and this family formed in Bradford.”

Fogelman foreshadows that Kevin’s change after moving next door to Uncle Nicky and making strong bonds in Bradford is “kind of the launching pad for the rest of his life” and a “chapter in Kevin’s life he will look back on and maybe consider a turning point.”

Randall Pearson

On the flip side, Kevin’s conflict with Randall may be coinciding with an intense time for the councilman.

“Randall is a giant back half of this season coming up with a couple of specialized episodes that really get inside of him in terms of what’s going on in his wiring and what’s going on in his mind. Sterling was just in the writer’s room and we’re doing this special episode towards the end of the season,” Fogelman says.

“This is a character who was left for adoption as a child which immediately creates some identity issues. He lost his father at a very formative age and then, upon finally reuniting with his birth father, lost his second father [William],” he recalls. “He’s a guy who tries to keep control and for a guy who tries to please and be everything to everybody. He’s so decent and good, but constantly having questions about his identity. You can imagine the pressure and toll it can take.”

As far as more R&R time to come, the mother-son pair’s secret pact about Rebecca’s memory loss may complicate their familial relationships. “There’s a lot going on,” Fogelman teases.

Kate Pearson

Kate has had her ups and downs, both individually and in her marriage with Toby. Not only did he initially keep his newfound CrossFit interest a secret, but she also kept baby Jack’s first solid food milestone a secret at first as well. Now, Toby confides in his new community via a friendly text group, excluding his wife and including a mysterious female friend (or something more?) nicknamed LadyKryptonite5.

“They’re in a challenging pocket of year. I don’t think it’s crazy that almost every season you’ve seen different couples at crossroads,” Fogelman says of new parents Kate and Toby.

“Last season we had a lot of struggle between Randall and Beth and second season Jack and Rebecca had a lot of moments in crisis. Now, we’re in that period of time with Kate and Toby. There’s a lot going on here,” he says. “Kate is feeling like she’s home alone with a child, meanwhile Toby is feeling left out. They’re dealing with a baby who has special needs and he’s putting extra strain on them as a couple. They have a very challenging back half of the season but I don’t think it’s going to go quite where people think it’s going to go.”

As for weight loss becoming a contributing factor in their relationship, Fogelman explains “it’s also a lot about secrets being kept and community being formed.”

“We’ve covered [weight loss] quite a lot and it’s an identifiable quality when partners are changing whether it’s physically or emotionally and you feel like you’re not. It was never just about the weight loss for her and for them,” he shares. “The feeling of when not just one person is losing weight and you’re not but also simultaneously it’s accomplishing a shared goal at the exact moment where it was hardest for you to do it. That’s not just about weight but it’s also about psychology and the psychology of a relationship.”

RELATED: This Is Us‘ Chrissy Metz And Chris Sullivan Hint At ‘Secrets’ Affecting Kate And Toby’s Marriage

And will LadyKryptonite5’s identity be revealed? “As we get into the back half of the season, I think the question also starts coming from Kate’s perspective of not only who is this person — that’ll happen and will be the surprising answer for people — but also secondarily, what is it that is pulling Toby into the gym so much?” Fogelman teases. “We’re going to be tapping into some intense marital stuff that is specific to these two characters and their situation with baby Jack. It’s interesting stuff. It would be very hard for people to guess where they’re headed.”

Another man to be learned about is Kate’s boyfriend Marc from her past.

“It’s a big part of our back half of the season. In the beginning of the rest of the season, we’re going into these individualized episodes with the Big Three that are interconnected in time and everyone gets their own focused episode,” Fogelman shares. “Marc plays a very big part in the culmination of it all. A lot of answers will be caught in there as to what formed Kate in this stage of her life. This vulnerable young woman who lost the most important person in her life and then finally pulling herself back on to her feet. The first relationship became this guy who there is something other about, that could be a backburner for this young woman. What this is and how it affected her is definitely something we’re heading into.”

Nicky Pearson

Uncle Nicky is here to stay with the Pearson family, though he may return to Bradford without Kevin. And we may learn more about the Pearson brothers’ bond juxtaposed with the conflicts of what Kevin and Randall will go through.

“We’ve seen a lot of stuff that would involve Milo and Michael on camera already but obviously the second you see those two together as younger men there’s something instantly impactful about them, especially considering that we’re going into brother territory with Randall and Kevin,” Fogelman says. “It’s definitely something we want to return to.”

Though we learned more about Nicky’s past, specifically his ex-girlfriend Sally, that romance won’t be featured this season. “We want to very much. We don’t quite have plans for her yet for this season. But it’s something we’re all very interested in,” he shares.

Season 4 will return with new episodes in January.

This Is Us airs Tuesdays (9 p.m. ET) on NBC.